1. Technical Field
The technology described herein relates generally to wireless networking. More particularly, the technology relates generally to allocating frequency resources to each of a plurality of stations (STAs) in a Wireless Local Area Network (WLAN).
2. Description of the Related Art
A WLAN is being standardized by the IEEE (Institute of Electrical and Electronics Engineers) Part 11 under the name of “Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications.” A series of standards have been adopted as the WLAN evolved, including IEEE Std 802.11™-2012 (March 2012). The IEEE Std 802.11™-2012 was subsequently amended by IEEE Std 802.11ae™-2012, IEEE Std 802.11aa™-2012, IEEE Std 802.11ad™-2012, and IEEE Std 802.11ac™-2013. These standards are each hereby incorporated by reference herein in their entirety.
Recently, a high efficiency WLAN for enhancing system throughput in high-density scenarios is being developed by the IEEE 802.11ax task group. In such WLAN scenarios, a transmitting device may transmit an Orthogonal Frequency Division Multiple Access (OFDMA) frame having respective data for each of a plurality of receiving devices. Within the OFDMA frame, the respective data for the receiving devices may be transmitted in one more frequency region (sub-bands) respectively allocated to the receiving devices. Each sub-band includes a plurality of subcarriers at different frequencies.
The respective channels between the transmitting device and each of the receiving devices may be frequency selective, which means the channel magnitude changes over frequency. In the design of an OFDMA wireless network, it is possible to take advantage of the frequency selectivity of the channel. For instance, the transmitting device can schedule downlink (DL) transmission for several receiving devices within a downlink OFDMA PHY Protocol Data Unit (PPDU), where the information related to each receiving device is placed in the sub-band wherein the receiving device experiences higher channel magnitude.
The sub-bands that have a high channel magnitude for each receiving device may be determined in order to use sub-bands optimally.